The April 5, 2012 exchange between Mr. Dimon and Ina Drew, the executive in charge of the bank’s Chief Investment Office at the time, is a new detail about J.P. Morgan’s handling of the episode that emerged Friday as the Senate Permanent Subcommittee on Investigations released more than 2,500 pages of documents it collected as part of an investigation into the trades.

The documents offered new insight into the dialogue between top bank officials before Mr. Dimon on April 13, 2012 publicly dismissed concerns around the trades as a “tempest in a teapot.” He later admitted he was wrong, and the company said no executives, including Mr. Dimon, deliberately misled investors.

Mr. Dimon was out of the office during a critical 10-day period that included the April 6, 2012 Wall Street Journal story that named the trader, Bruno Iksil, and noted how his positions on certain corporate credit indexes were roiling debt markets. Mr. Dimon was on vacation for four of those days and on business trips in Houston, Dallas and New Orleans the rest of the time, the company previously said. Most of Mr. Dimon’s time away was on business, a J.P. Morgan spokesman reiterated Friday.

Many of the documents gathered by the subcommittee were released last March when the Senate panel published a 301-page report and 597 pages of additional exhibits alleging J.P. Morgan brushed off internal warnings and misled regulators and investors about the scope of losses last year.

The trades ultimately cost the company more than $6 billion. This year the company also agreed to pay roughly $1 billion to settle several probes of the episode.

The Senate panel reviewed 90,000 documents and included 1,654 footnotes in its March report. The documents released Friday correspond with the footnotes.

The exchange between Mr. Dimon and Ms. Drew followed an e-mail Ms. Drew sent April 5, 2012 at 5:58 p.m., to the bank’s operating committee – a group that includes Mr. Dimon and the executives who report to him.

The e-mail, which was released in March, was her attempt to provide a summary of the trading activities in advance of The Wall Street Journal story. She acknowledged that “mistakes” had been made and that losses were $500 million to date, but that earnings for the first quarter had not been affected because of gains elsewhere. She pledged to answer any questions at an operating committee meeting the following Monday.

Two minutes later Mr. Dimon sent her a response: “Ok. send me some info. Also how does it relat (sic) or not to our wind down credit exotics book?”

Ms. Drew responded that evening by explaining to her boss that the positions at issue were different than the “wind down in the ib credit exotics book” and that she “targeted” this particular portfolio within the Chief Investment Office for a reduction as a way of lessening a measure known as risk weighted assets.

Such assets, known as RWA for short, affect how much capital the bank is required to hold under new international rules.

“I have been assessing the trade off between p l and rwa for the quarter,” she wrote, an apparent reference to the losses the portfolio had taken as compared to plans for a reduction in risk weighted assets.

“I can go over all the technicals with you at any time,” she told her boss in the email. “I wanted to this week but understood you were on vacation.”